Get rid of XML::Simple

[alip]

Quoting perldoc:

STATUS OF THIS MODULE
    The use of this module in new code is strongly discouraged. Other
    modules are available which provide more straightforward and consistent
    interfaces. In particular, XML::LibXML is highly recommended and you can
    refer to Perl XML::LibXML by Example
    <http://grantm.github.io/perl-libxml-by-example/> for a tutorial
    introduction.

    XML::Twig is another excellent alternative.

    The major problems with this module are the large number of options
    (some of which have unfortunate defaults) and the arbitrary ways in
    which these options interact - often producing unexpected results.

    Patches with bug fixes and documentation fixes are welcome, but new
    features are unlikely to be added.

Our primary concern is the virtualization bits that seems to be failing randomly with new XML::Simple:

lib/Rex/Cloud/Amazon.pm
lib/Rex/Virtualization/LibVirt/hypervisor.pm
lib/Rex/Virtualization/LibVirt/clone.pm
lib/Rex/Virtualization/LibVirt/vncdisplay.pm
lib/Rex/Virtualization/LibVirt/dumpxml.pm
lib/Rex/Virtualization/LibVirt/create.pm
lib/Rex/Virtualization/LibVirt/info.pm
lib/Rex/Virtualization/Docker/create.pm
lib/Rex/Virtualization/VBox/create.pm
lib/Rex/Virtualization/VBox/info.pm
lib/Rex/Inventory.pm